Yamada-san is an office lady whose hobby is self-bondage masturbation. Since her perverted tastes were discovered by her boss previously, Yamada-san has been subjected to unreasonable training. She is tied up and left alone in a deserted public toilet (for men). Eventually, she is found by a homeless man ...!? She literally becomes a dirty toilet girl and fulfills all the man's desires!
Yeah, those two tags are wrong for this gallery, so anyone can help by downvoting those tags. Scat requires actual depiction of feces (any presence is ok, but here it's only mentioned, not drawn). Moreover in this case, the namespace should be male and not female, if it was visible. Cophrophagia requires normal gallery presence. 1 page isn't enough for a 20 page doujinshi. It also requires the scat tag, so it wouldn't be applicable here anyways.
The first one was vastly better than this. I much prefer the concept of her and her boss having kinky fun than her randomly being tied up in a toilet. The first was very creative, this is so...mundane by comparison. Like how many thousands of doujin have this exact same kind of setup? The only difference is the art style of this artist is exquisite. Hopefully if a 3rd volume gets made it will be closer to the first than this one.